The invention relates to an orthopaedic ratcheting forceps and specifically to a forceps used to manipulate and hold the bone for fixation of fractures.
The prior art shows a multitude of manipulating devices for use during orthopaedic surgery. An exemplary forceps according to the preamble of the main claim of this invention is shown in WO 89/06939 (U.S. Pat. No. 4,896,661). Beside the fact of the possibility to interchange tips of the forceps as shown in said application, another important practical point for the surgeon is the possibility to change the attack point of the forceps, i.e., to have a reversible ratchet mechanism. The advantage of the ratchet according to said PCT application resides in the fact, as shown in FIGS. 9, 8 and 9, that through switching a lever through three switching positions the forceps can move freely (FIG. 9, neutral position) or in either direction (FIG. 10 or FIG. 11, respectively). Although this approach facilitates the work of the surgeon, it has been found not to be entirely satisfactory. The mechanism is difficult to manipulate with only one hand.
Another known forceps is disclosed in U.S. Pat. No. 5,674,244. The pliers according to this document have the advantage that almost all of the ratcheting structure is within the handles and do not extend beyond the outer form of the instrument. There is provided a spring to exert the counter-force to open the pliers, when the release button is pushed. The advantage of reduced dimensions of the forceps goes with the practical disadvantage in activating the locking device of the pliers between the handles.